This is because the primary function of this stage is the fixation of carbon. which involves making simple sugars from carbon dioxide and water. It involves addition of inorganic carbon (carbon dioxide) to an organic molecule or molecules by plants, this occurs during the light independent stage reaction of photosynthesis and is the first step in the Calvin cycle.
1. Early earth had no ozone layer, which means it was most likely extremely hot.
2. Young earth had no oxygen and life needs oxygen in order to survive.
3. There where so many natural disasters happening all the time, like volcanic eruptions and constant impact with meteorites and asteroids.
-Extra one (4. Earth originally had no ocean and water. Oceans eventually formed from the water vapor released from the volcanic eruptions, but before that there was nothing.)
Answer:
Eosinophils
Explanation:
These are type of White blood cells W.B.C ,present almost 2% of white cells . About twice the size of red blood cells , Nucleus is bi lobed . They are often used for parasite attack , Inactivate inflammation and production of substances .
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

In the science world today, both the natural regeneration and stem cell therapy can be used to generate new cells and both processes have thier advantages and disadvantages. The following are the advantages of natural regeneration over stem cell transplants:
1. Natural regeneration is cheaper compares to stem cell transplant.
2. The process of natural regeneration is safe and does not involve the fear of unknown, long time effects like that of stem cell transplant.
3. Naturally regenerated cells can not be rejected by the patient's body but a stem cell transplanted cell can be rejected by the patient's body.